The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Anna-liisa Laine - One of the best experts on this subject based on the ideXlab platform.
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Pathogen dynamics under both bottom-up host resistance and top-down Hyperparasite attack.
The Journal of applied ecology, 2018Co-Authors: Steven R. Parratt, Anna-liisa LaineAbstract:The relative importance of bottom‐up versus top‐down control of population dynamics has been the focus of much debate. In infectious disease biology, research is typically focused on the bottom‐up process of host resistance, wherein the direction of control flows from the lower to the higher trophic level to impact on pathogen population size and epidemiology. However, the importance of top‐down control by a pathogen's natural enemies has been mostly overlooked. Here, we explore the effects of, and interaction between, host genotype (i.e., genetic susceptibility to pathogen infection) and infection by a hyperparasitic fungus, Ampelomyces spp., on the establishment and early epidemic growth and transmission of a powdery mildew plant pathogen (Podosphaera plantaginis). We used a semi‐natural field experiment to contrast the impacts of Hyperparasite infection, host‐plant resistance and spatial structure to reveal the key factors that determine pathogen spread. We then used a laboratory‐based inoculation approach to test whether the field experiment results hold across multiple pathogen–host genetic combinations and to explore Hyperparasite effects on the pathogen's later life‐history stages. We found that Hyperparasite infection had a negligible effect on within‐host infection development and between‐host spread of the pathogen during the onset of epidemics. In contrast, host‐plant resistance was the major determinant of whether plants became infected, and host genotype and proximity to an infection source determined infection severity. Our laboratory study showed that, while the interaction between host and pathogen genotypes was the key determinant of infection outcome, hyperparasitism did, on average, reduce the severity of infection. Moreover, Hyperparasite infection negatively influenced the production of the pathogen's overwintering structures. Synthesis and applications. Our results suggest that bottom‐up host resistance affects pathogen spread, but top‐down control of powdery mildew pathogens is likely more effective against later life‐history stages. Further, while hyperparasitism in this system can reduce early pathogen growth under stable laboratory conditions, this effect is not detectable in a semi‐natural environment. Considering the effects of Hyperparasites at multiple points in pathogen's life history will be important when considering Hyperparasite‐derived biocontrol measures in other natural and agricultural systems.
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Parrattt_&_Laine_LabExpt1_data
2018Co-Authors: Steven Parratt, Anna-liisa LaineAbstract:Response and independent variable used to analyse the effect of Hyperparasite infection and host genotype on pathogen growth in the laboratory
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Local adaptation at higher trophic levels: contrasting Hyperparasite-pathogen infection dynamics in the field and laboratory
Molecular ecology, 2016Co-Authors: Steven R. Parratt, Benoit Barrès, Rachel M. Penczykowski, Anna-liisa LaineAbstract:Predicting and controlling infectious disease epidemics is a major challenge facing the management of agriculture, human and wildlife health. Co-evolutionarily derived patterns of local adaptation among pathogen populations have the potential to generate variation in disease epidemiology; however, studies of local adaptation in disease systems have mostly focused on interactions between competing pathogens or pathogens and their hosts. In nature, parasites and pathogens are also subject to attack by hyperparasitic natural enemies that can severely impact upon their infection dynamics. However, few studies have investigated whether this interaction varies across combinations of pathogen–Hyperparasite strains, and whether this influences Hyperparasite incidence in natural pathogen populations. Here, we test whether the association between a hyperparasitic fungus, Ampelomyces, and a single powdery mildew host, Podosphaera plantaginis, varies among genotype combinations, and whether this drives Hyperparasite incidence in nature. Laboratory inoculation studies reveal that genotype, genotype × genotype interactions and local adaptation affect Hyperparasite infection. However, observations of a natural pathogen metapopulation reveal that spatial rather than genetic factors predict the risk of Hyperparasite presence. Our results highlight how sensitive the outcome of biocontrol using Hyperparasites is to selection of Hyperparasite strains.
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The role of hyperparasitism in microbial pathogen ecology and evolution
The ISME Journal, 2016Co-Authors: Steven R. Parratt, Anna-liisa LaineAbstract:Many micro-organisms employ a parasitic lifestyle and, through their antagonistic interactions with host populations, have major impacts on human, agricultural and natural ecosystems. Most pathogens are likely to host parasites of their own, that is, Hyperparasites, but how nested chains of parasites impact on disease dynamics is grossly neglected in the ecological and evolutionary literature. In this minireview we argue that the diversity and dynamics of micro-Hyperparasites are an important component of natural host–pathogen systems. We use the current literature from a handful of key systems to show that observed patterns of pathogen virulence and disease dynamics may well be influenced by Hyperparasites. Exploring these factors will shed light on many aspects of microbial ecology and disease biology, including resistance–virulence evolution, apparent competition, epidemiology and ecosystem stability. Considering the importance of Hyperparasites in natural populations will have applied consequences for the field of biological control and therapeutic science, where hyperparastism is employed as a control mechanism but not necessarily ecologically understood.
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A Hyperparasite affects the population dynamics of a wild plant pathogen
Molecular ecology, 2014Co-Authors: Charlotte Tollenaere, Steven R. Parratt, B. Pernechele, Hannu Mäkinen, Márk Z. Németh, Gábor M. Kovács, Levente Kiss, Ayco J. M. Tack, Anna-liisa LaineAbstract:Assessing the impact of natural enemies of plant and animal pathogens on their host's population dynamics is needed to determine the role of Hyperparasites in affecting disease dynamics, and their potential for use in efficient control strategies of pathogens. Here, we focus on the long-term study describing metapopulation dynamics of an obligate pathogen, the powdery mildew (Podosphaera plantaginis) naturally infecting its wild host plant (Plantago lanceolata) in the fragmented landscape of the Aland archipelago (southwest Finland). Regionally, the pathogen persists through a balance of extinctions and colonizations, yet factors affecting extinction rates remain poorly understood. Mycoparasites of the genus Ampelomyces appear as good candidates for testing the role of a Hyperparasite, i.e. a parasite of other parasites, in the regulation of their fungal hosts' population dynamics. For this purpose, we first designed a quantitative PCR assay for detection of Ampelomyces spp. in field-collected samples. This newly developed molecular test was then applied to a large-scale sampling within the Aland archipelago, revealing that Ampelomyces is a widespread Hyperparasite in this system, with high variability in prevalence among populations. We found that the Hyperparasite was more common on leaves where multiple powdery mildew strains coexist, a pattern that may be attributed to differential exposure. Moreover, the prevalence of Ampelomyces at the plant level negatively affected the overwinter survival of its fungal host. We conclude that this Hyperparasite may likely impact on its host population dynamics and argue for increased focus on the role of Hyperparasites in disease dynamics.
Kristoffer Hylander - One of the best experts on this subject based on the ideXlab platform.
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temporal dynamics and biocontrol potential of a Hyperparasite on coffee leaf rust across a landscape in arabica coffee s native range
Agriculture Ecosystems & Environment, 2021Co-Authors: Beyene Zewdie, Ayco J. M. Tack, Biruk Ayalew, Girma Adugna, Sileshi Nemomissa, Kristoffer HylanderAbstract:Abstract Agroforestry systems can provide habitats for a rich biodiversity including multitrophic interactions, which presents opportunities to develop natural pest control. Shade coffee systems in several coffee growing areas of the world host such unique habitats where pests and their natural enemies interact. One of the major global challenges for coffee production, coffee leaf rust caused by the fungal pathogen Hemileia vastatrix is attacked by the fungal Hyperparasite, Lecanicillium lecanii. However, we lack insights in the dynamics and biocontrol potential of the Hyperparasite on coffee leaf rust from landscapes in Arabica coffee’s native range. To understand the temporal dynamics across landscapes and environmental drivers of the rust and Hyperparasite, and the potential for biocontrol of the rust by the Hyperparasite, we studied the rust and Hyperparasite during the dry and wet seasons for three consecutive years at 60 sites across a gradient of coffee management in southwestern Ethiopia. We found that coffee leaf rust was more severe during the dry season, whereas the Hyperparasite was more severe during the wet season in two out of three years. The rust growth rate from the wet to the dry season transition was negatively related to the Hyperparasite index during the wet season, implying a potential top-down control. Coffee leaf rust was generally more severe at lower altitudes in the dry season, whereas the Hyperparasite was more severe at high altitude. The rust incidence increased with management intensity, while the Hyperparasite was more common under less intensive management. This study could be interesting in that it represents a landscape where Arabica coffee originated and the rust and Hyperparasite might have a long co-evolutionary history. Our findings highlight the potential of the Hyperparasite to suppress the rust’s growth rate from the wet to dry season transition when the rust severity could otherwise be at its peak. We show that less intensively managed landscapes with dense shade levels are likely to increase Hyperparasite abundance and result in an improved top-down control of the rust. However, more detailed knowledge is needed on the interaction of these species to assess its importance for reducing rust induced yield losses or the risk of rust outbreaks.
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Temporal dynamics and biocontrol potential of a Hyperparasite on coffee leaf rust across a landscape in Arabica coffee’s native range
Agriculture Ecosystems & Environment, 1Co-Authors: Beyene Zewdie, Ayco J. M. Tack, Biruk Ayalew, Girma Adugna, Sileshi Nemomissa, Kristoffer HylanderAbstract:Abstract Agroforestry systems can provide habitats for a rich biodiversity including multitrophic interactions, which presents opportunities to develop natural pest control. Shade coffee systems in several coffee growing areas of the world host such unique habitats where pests and their natural enemies interact. One of the major global challenges for coffee production, coffee leaf rust caused by the fungal pathogen Hemileia vastatrix is attacked by the fungal Hyperparasite, Lecanicillium lecanii. However, we lack insights in the dynamics and biocontrol potential of the Hyperparasite on coffee leaf rust from landscapes in Arabica coffee’s native range. To understand the temporal dynamics across landscapes and environmental drivers of the rust and Hyperparasite, and the potential for biocontrol of the rust by the Hyperparasite, we studied the rust and Hyperparasite during the dry and wet seasons for three consecutive years at 60 sites across a gradient of coffee management in southwestern Ethiopia. We found that coffee leaf rust was more severe during the dry season, whereas the Hyperparasite was more severe during the wet season in two out of three years. The rust growth rate from the wet to the dry season transition was negatively related to the Hyperparasite index during the wet season, implying a potential top-down control. Coffee leaf rust was generally more severe at lower altitudes in the dry season, whereas the Hyperparasite was more severe at high altitude. The rust incidence increased with management intensity, while the Hyperparasite was more common under less intensive management. This study could be interesting in that it represents a landscape where Arabica coffee originated and the rust and Hyperparasite might have a long co-evolutionary history. Our findings highlight the potential of the Hyperparasite to suppress the rust’s growth rate from the wet to dry season transition when the rust severity could otherwise be at its peak. We show that less intensively managed landscapes with dense shade levels are likely to increase Hyperparasite abundance and result in an improved top-down control of the rust. However, more detailed knowledge is needed on the interaction of these species to assess its importance for reducing rust induced yield losses or the risk of rust outbreaks.
Christopher A. Gilligan - One of the best experts on this subject based on the ideXlab platform.
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Selecting Hyperparasites for biocontrol of Dutch elm disease.
Proceedings of the Royal Society of London. Series B: Biological Sciences, 1999Co-Authors: Jonathan Swinton, Christopher A. GilliganAbstract:Hyperparasites in the form of cytoplasmic RNA elements have been proposed as a biological control agent for Dutch elm disease. We characterized the range of outcomes likely to follow the introduction of such an agent by modelling the resultant population dynamics as an ecological interaction between the wild, 'target', fungus and the hyperparasitized 'control' fungus. We used data from the 1970s epidemic of Dutch elm disease in the UK to parameterize the population dynamics of the target fungus, and considered the success of control across a wide range of possibilities for the lethality and transmissibility of the modified control fungus. We decomposed Hyperparasite transmissibility into horizontal transmissibility (the ability to colonize previously unparasitized target fungal hosts) and vertical transmissibility (the ability of control fungus to establish new colonies). There is an invasion threshold for both horizontal and vertical transmissibility. As vertical transmission is further increased, there is another threshold at which the target fungus is eradicated because of competitive exclusion by the control fungus. In contrast, eradication by raising horizontal transmission may never succeed because the target fungus needs to be present to support new cases through this route. Between these two thresholds for invasion and exclusion, control and target fungus may coexist. Using a stochastic, spatially extended model, we showed that predictions of success based on high competitive ability of the control fungus (i.e. high vertical transmission) are likely to be more robust than those based on the high degree to which the control fungus can cause target fungus to be hyperparasitized (i.e. high horizontal transmission).
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Spatial heterogeneity in three species, plant–parasite–Hyperparasite, systems
Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 1998Co-Authors: Katrin White, Christopher A. GilliganAbstract:This paper addresses the question of how heterogeneity may evolve due to interactions between the dynamics and movement of three–species systems involving hosts, parasites and Hyperparasites in homogeneous environments. The models are motivated by the spread of soil–borne parasites within plant populations, where the Hyperparasite is used as a biological control agent but where patchiness in the distribution of the parasite occurs, even when environmental conditions are apparently homogeneous. However, the models are introduced in generic form as three–species reaction–diffusion systems so that they have broad applicability to a range of ecological systems. We establish necessary criteria for the occurrence of population–driven patterning via diffusion–driven instability. Sufficient conditions are obtained for restricted cases with no host movement. The criteria are similar to those for the well–documented two–species reaction–diffusion system, although more possibilities arise for spatial patterning with three species. In particular, temporally varying patterns, that may be responsible for the apparent drifting of hot–spots of disease and periodic occurrence of disease at a given location, are possible when three species interact. We propose that the criteria can be used to screen population interactions, to distinguish those that cannot cause patterning from those that may give rise to population–driven patterning. This establishes a basic dynamical ‘landscape’ against which other perturbations, including environmentally driven variations, can be analysed and distinguished from population–driven patterns. By applying the theory to a specific model example for host–parasite–Hyperparasite interactions both with and without host movement, we show directly how the evolution of spatial pattern is related to biologically meaningful parameters. In particular, we demonstrate that when there is strong density dependence limiting host growth, the pattern is stable over time, whereas with less stable underlying host growth, the pattern varies with time.
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spatial heterogeneity in three species plant parasite Hyperparasite systems
Philosophical Transactions of the Royal Society B, 1998Co-Authors: Katrin White, Christopher A. GilliganAbstract:This paper addresses the question of how heterogeneity may evolve due to interactions between the dynamics and movement of three–species systems involving hosts, parasites and Hyperparasites in homogeneous environments. The models are motivated by the spread of soil–borne parasites within plant populations, where the Hyperparasite is used as a biological control agent but where patchiness in the distribution of the parasite occurs, even when environmental conditions are apparently homogeneous. However, the models are introduced in generic form as three–species reaction–diffusion systems so that they have broad applicability to a range of ecological systems. We establish necessary criteria for the occurrence of population–driven patterning via diffusion–driven instability. Sufficient conditions are obtained for restricted cases with no host movement. The criteria are similar to those for the well–documented two–species reaction–diffusion system, although more possibilities arise for spatial patterning with three species. In particular, temporally varying patterns, that may be responsible for the apparent drifting of hot–spots of disease and periodic occurrence of disease at a given location, are possible when three species interact. We propose that the criteria can be used to screen population interactions, to distinguish those that cannot cause patterning from those that may give rise to population–driven patterning. This establishes a basic dynamical ‘landscape’ against which other perturbations, including environmentally driven variations, can be analysed and distinguished from population–driven patterns. By applying the theory to a specific model example for host–parasite–Hyperparasite interactions both with and without host movement, we show directly how the evolution of spatial pattern is related to biologically meaningful parameters. In particular, we demonstrate that when there is strong density dependence limiting host growth, the pattern is stable over time, whereas with less stable underlying host growth, the pattern varies with time.
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Population Dynamics of a Parasite and Hyperparasite in a Closed System: Model Analysis and Parameter Estimation
Proceedings of the Royal Society of London. Series B: Biological Sciences, 1996Co-Authors: Simon Gubbins, Christopher A. GilliganAbstract:In this paper, we introduce and test models of the dynamics of a parasite and Hyperparasite in a closed system from which the parasite's host is excluded. The models are tested against data for the temporal dynamics of a fungal plant parasite of lettuce, Sclerotinia minor, and a fungal Hyperparasite, Sporidesmium sclerotivorum. The models are developed by treating the Hyperparasite-parasite dynamics as a classical predator-prey system, but then expanding the prey component into a compartmental system of susceptible (uninfected) and infected parasites. The resulting hybrid model enables the separation of the dynamics of susceptible parasites, which are capable of causing disease, and infected parasites, which support reproduction of the Hyperparasite. The influence of different functional and numerical responses are compared by analytical results and by parameter estimation.
Ayco J. M. Tack - One of the best experts on this subject based on the ideXlab platform.
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temporal dynamics and biocontrol potential of a Hyperparasite on coffee leaf rust across a landscape in arabica coffee s native range
Agriculture Ecosystems & Environment, 2021Co-Authors: Beyene Zewdie, Ayco J. M. Tack, Biruk Ayalew, Girma Adugna, Sileshi Nemomissa, Kristoffer HylanderAbstract:Abstract Agroforestry systems can provide habitats for a rich biodiversity including multitrophic interactions, which presents opportunities to develop natural pest control. Shade coffee systems in several coffee growing areas of the world host such unique habitats where pests and their natural enemies interact. One of the major global challenges for coffee production, coffee leaf rust caused by the fungal pathogen Hemileia vastatrix is attacked by the fungal Hyperparasite, Lecanicillium lecanii. However, we lack insights in the dynamics and biocontrol potential of the Hyperparasite on coffee leaf rust from landscapes in Arabica coffee’s native range. To understand the temporal dynamics across landscapes and environmental drivers of the rust and Hyperparasite, and the potential for biocontrol of the rust by the Hyperparasite, we studied the rust and Hyperparasite during the dry and wet seasons for three consecutive years at 60 sites across a gradient of coffee management in southwestern Ethiopia. We found that coffee leaf rust was more severe during the dry season, whereas the Hyperparasite was more severe during the wet season in two out of three years. The rust growth rate from the wet to the dry season transition was negatively related to the Hyperparasite index during the wet season, implying a potential top-down control. Coffee leaf rust was generally more severe at lower altitudes in the dry season, whereas the Hyperparasite was more severe at high altitude. The rust incidence increased with management intensity, while the Hyperparasite was more common under less intensive management. This study could be interesting in that it represents a landscape where Arabica coffee originated and the rust and Hyperparasite might have a long co-evolutionary history. Our findings highlight the potential of the Hyperparasite to suppress the rust’s growth rate from the wet to dry season transition when the rust severity could otherwise be at its peak. We show that less intensively managed landscapes with dense shade levels are likely to increase Hyperparasite abundance and result in an improved top-down control of the rust. However, more detailed knowledge is needed on the interaction of these species to assess its importance for reducing rust induced yield losses or the risk of rust outbreaks.
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A Hyperparasite affects the population dynamics of a wild plant pathogen
Molecular ecology, 2014Co-Authors: Charlotte Tollenaere, Steven R. Parratt, B. Pernechele, Hannu Mäkinen, Márk Z. Németh, Gábor M. Kovács, Levente Kiss, Ayco J. M. Tack, Anna-liisa LaineAbstract:Assessing the impact of natural enemies of plant and animal pathogens on their host's population dynamics is needed to determine the role of Hyperparasites in affecting disease dynamics, and their potential for use in efficient control strategies of pathogens. Here, we focus on the long-term study describing metapopulation dynamics of an obligate pathogen, the powdery mildew (Podosphaera plantaginis) naturally infecting its wild host plant (Plantago lanceolata) in the fragmented landscape of the Aland archipelago (southwest Finland). Regionally, the pathogen persists through a balance of extinctions and colonizations, yet factors affecting extinction rates remain poorly understood. Mycoparasites of the genus Ampelomyces appear as good candidates for testing the role of a Hyperparasite, i.e. a parasite of other parasites, in the regulation of their fungal hosts' population dynamics. For this purpose, we first designed a quantitative PCR assay for detection of Ampelomyces spp. in field-collected samples. This newly developed molecular test was then applied to a large-scale sampling within the Aland archipelago, revealing that Ampelomyces is a widespread Hyperparasite in this system, with high variability in prevalence among populations. We found that the Hyperparasite was more common on leaves where multiple powdery mildew strains coexist, a pattern that may be attributed to differential exposure. Moreover, the prevalence of Ampelomyces at the plant level negatively affected the overwinter survival of its fungal host. We conclude that this Hyperparasite may likely impact on its host population dynamics and argue for increased focus on the role of Hyperparasites in disease dynamics.
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Temporal dynamics and biocontrol potential of a Hyperparasite on coffee leaf rust across a landscape in Arabica coffee’s native range
Agriculture Ecosystems & Environment, 1Co-Authors: Beyene Zewdie, Ayco J. M. Tack, Biruk Ayalew, Girma Adugna, Sileshi Nemomissa, Kristoffer HylanderAbstract:Abstract Agroforestry systems can provide habitats for a rich biodiversity including multitrophic interactions, which presents opportunities to develop natural pest control. Shade coffee systems in several coffee growing areas of the world host such unique habitats where pests and their natural enemies interact. One of the major global challenges for coffee production, coffee leaf rust caused by the fungal pathogen Hemileia vastatrix is attacked by the fungal Hyperparasite, Lecanicillium lecanii. However, we lack insights in the dynamics and biocontrol potential of the Hyperparasite on coffee leaf rust from landscapes in Arabica coffee’s native range. To understand the temporal dynamics across landscapes and environmental drivers of the rust and Hyperparasite, and the potential for biocontrol of the rust by the Hyperparasite, we studied the rust and Hyperparasite during the dry and wet seasons for three consecutive years at 60 sites across a gradient of coffee management in southwestern Ethiopia. We found that coffee leaf rust was more severe during the dry season, whereas the Hyperparasite was more severe during the wet season in two out of three years. The rust growth rate from the wet to the dry season transition was negatively related to the Hyperparasite index during the wet season, implying a potential top-down control. Coffee leaf rust was generally more severe at lower altitudes in the dry season, whereas the Hyperparasite was more severe at high altitude. The rust incidence increased with management intensity, while the Hyperparasite was more common under less intensive management. This study could be interesting in that it represents a landscape where Arabica coffee originated and the rust and Hyperparasite might have a long co-evolutionary history. Our findings highlight the potential of the Hyperparasite to suppress the rust’s growth rate from the wet to dry season transition when the rust severity could otherwise be at its peak. We show that less intensively managed landscapes with dense shade levels are likely to increase Hyperparasite abundance and result in an improved top-down control of the rust. However, more detailed knowledge is needed on the interaction of these species to assess its importance for reducing rust induced yield losses or the risk of rust outbreaks.
Beyene Zewdie - One of the best experts on this subject based on the ideXlab platform.
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temporal dynamics and biocontrol potential of a Hyperparasite on coffee leaf rust across a landscape in arabica coffee s native range
Agriculture Ecosystems & Environment, 2021Co-Authors: Beyene Zewdie, Ayco J. M. Tack, Biruk Ayalew, Girma Adugna, Sileshi Nemomissa, Kristoffer HylanderAbstract:Abstract Agroforestry systems can provide habitats for a rich biodiversity including multitrophic interactions, which presents opportunities to develop natural pest control. Shade coffee systems in several coffee growing areas of the world host such unique habitats where pests and their natural enemies interact. One of the major global challenges for coffee production, coffee leaf rust caused by the fungal pathogen Hemileia vastatrix is attacked by the fungal Hyperparasite, Lecanicillium lecanii. However, we lack insights in the dynamics and biocontrol potential of the Hyperparasite on coffee leaf rust from landscapes in Arabica coffee’s native range. To understand the temporal dynamics across landscapes and environmental drivers of the rust and Hyperparasite, and the potential for biocontrol of the rust by the Hyperparasite, we studied the rust and Hyperparasite during the dry and wet seasons for three consecutive years at 60 sites across a gradient of coffee management in southwestern Ethiopia. We found that coffee leaf rust was more severe during the dry season, whereas the Hyperparasite was more severe during the wet season in two out of three years. The rust growth rate from the wet to the dry season transition was negatively related to the Hyperparasite index during the wet season, implying a potential top-down control. Coffee leaf rust was generally more severe at lower altitudes in the dry season, whereas the Hyperparasite was more severe at high altitude. The rust incidence increased with management intensity, while the Hyperparasite was more common under less intensive management. This study could be interesting in that it represents a landscape where Arabica coffee originated and the rust and Hyperparasite might have a long co-evolutionary history. Our findings highlight the potential of the Hyperparasite to suppress the rust’s growth rate from the wet to dry season transition when the rust severity could otherwise be at its peak. We show that less intensively managed landscapes with dense shade levels are likely to increase Hyperparasite abundance and result in an improved top-down control of the rust. However, more detailed knowledge is needed on the interaction of these species to assess its importance for reducing rust induced yield losses or the risk of rust outbreaks.
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Temporal dynamics and biocontrol potential of a Hyperparasite on coffee leaf rust across a landscape in Arabica coffee’s native range
Agriculture Ecosystems & Environment, 1Co-Authors: Beyene Zewdie, Ayco J. M. Tack, Biruk Ayalew, Girma Adugna, Sileshi Nemomissa, Kristoffer HylanderAbstract:Abstract Agroforestry systems can provide habitats for a rich biodiversity including multitrophic interactions, which presents opportunities to develop natural pest control. Shade coffee systems in several coffee growing areas of the world host such unique habitats where pests and their natural enemies interact. One of the major global challenges for coffee production, coffee leaf rust caused by the fungal pathogen Hemileia vastatrix is attacked by the fungal Hyperparasite, Lecanicillium lecanii. However, we lack insights in the dynamics and biocontrol potential of the Hyperparasite on coffee leaf rust from landscapes in Arabica coffee’s native range. To understand the temporal dynamics across landscapes and environmental drivers of the rust and Hyperparasite, and the potential for biocontrol of the rust by the Hyperparasite, we studied the rust and Hyperparasite during the dry and wet seasons for three consecutive years at 60 sites across a gradient of coffee management in southwestern Ethiopia. We found that coffee leaf rust was more severe during the dry season, whereas the Hyperparasite was more severe during the wet season in two out of three years. The rust growth rate from the wet to the dry season transition was negatively related to the Hyperparasite index during the wet season, implying a potential top-down control. Coffee leaf rust was generally more severe at lower altitudes in the dry season, whereas the Hyperparasite was more severe at high altitude. The rust incidence increased with management intensity, while the Hyperparasite was more common under less intensive management. This study could be interesting in that it represents a landscape where Arabica coffee originated and the rust and Hyperparasite might have a long co-evolutionary history. Our findings highlight the potential of the Hyperparasite to suppress the rust’s growth rate from the wet to dry season transition when the rust severity could otherwise be at its peak. We show that less intensively managed landscapes with dense shade levels are likely to increase Hyperparasite abundance and result in an improved top-down control of the rust. However, more detailed knowledge is needed on the interaction of these species to assess its importance for reducing rust induced yield losses or the risk of rust outbreaks.